High School · Reasoning with Equations and Inequalities

CCSS.MATH.CONTENT.HSA.REI.B.4a

Use the method of completing the square to transform any quadratic equation in x into an equation of the form (x - p)² = q that has the same solutions. Derive the quadratic formula from this form.

Read this standard on the official Common Core site

Lessons that teach this standard

• Completing the Square, Step by Step

  Learn completing the square: why the method works geometrically, how to handle a leading coefficient, and how it produces vertex form and the quadratic formula.

• The Quadratic Formula: How and Why It Works

  Learn the quadratic formula, where it comes from, and how to use it to solve any quadratic equation, with worked examples and practice problems.